Metabolism Studies of Indole Derivatives Using a Staurosporine Producer,Streptomyces staurosporeus

From a tryptophan metabolic study, 3-(hydroxyacetyl)indole, indole-3-carboxaldehyde, and o-aminobenzoic acid were obtained as tryptophan metabolites from a staurosporine (1) producer, Streptomyces staurosporeus. A new tryptamine metabolite, (3aR,8aS)-1-acetyl-1,2,3,3a,8,8a-hexahydropyrrolo[2,3- b]indol-3a-ol (2), was isolated along with Nb-acetyltryptamine using S. staurosporeus fed with tryptamine. The unusual compound 2 was proposed as a further metabolite of Nb-acetyltryptamine through an enzymatic oxidative cyclization. Examination of the metabolites from the feeding of 5- and 6-fluorotryptamines using the same microorganism afforded the two novel compounds 3 and 4 as the 5- and 6-fluoro derivatives of 2. However, 5-hydroxytryptamine failed to generate the 5-hydroxy derivative of 2. Indole-ring-substituted metabolites of staurosporine (1) were not observed.